Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 3661.80004882813 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 4106.60009765625 | Thousand metric tons of contained nitrogen | 12.15% |
| 2005 | 4100 | Thousand metric tons of contained nitrogen | -0.16% |
| 2006 | 4100 | Thousand metric tons of contained nitrogen | 0.00% |
| 2007 | 4498 | Thousand metric tons of contained nitrogen | 9.71% |
| 2008 | 3920 | Thousand metric tons of contained nitrogen | -12.85% |
| 2009 | 3611 | Thousand metric tons of contained nitrogen | -7.88% |
| 2010 | 3620 | Thousand metric tons of contained nitrogen | 0.25% |
| 2011 | 3946 | Thousand metric tons of contained nitrogen | 9.01% |
| 2012 | 3942 | Thousand metric tons of contained nitrogen | -0.10% |
